Metal spray gun of the wire feed type



1945' A. P. SHEPARD EI'AL METAL SPRAY GUNS OF THE WIRE FEED TYPE Filed Dec. 1, 1941 9 Sheets-Sheet. 1

IN VENT OR-S Arthur P Shepard h'erberz .62 Irgkam a f 47,4

ATTOR EYJ 1945- A. P. SHEPARD ETAL 2,381,931

IIETAL SPRAY GUNS OF THE WIRE FEED TYPE ile ec- 1941 9 Sheets-Sheet 2 1% INN Qw Q A 8% a am 9: 3;; f'i-XIII &

INVENTOFS: Arthur P Jbeyoara' Herbal-f J lngbam ATTORNE 0 1945- A. F. SHEPARD ETAL 2,331,931

METAL SPRAY GUNS OF THE WIRE FEED TYPE Filed Dec. 1, 1941 9 Sheets-Sheet 3 J72 J03 M4 AA ArtA SZ g llerb ft 5.149%

ATTORNEY 14, 1945- A. P. SHEPARD ETAL METAL SPRAY GUNS OF THE WIRE FEED TYPE INVENTORJ A n): 117' P Jlrepard h'enberf J In gbam 6 "I M 7 ATTORNEYJ y w a & fimflw x m & Q 0* mm H w Q n h w mm x x a 0% mm Sm mm, N, Q m IF A. P. SHEPARD E'I'AL METAL SPRAY GUNS OF THE WIRE FEED TYPE Filed Dec. 1, 1941 9 Sheets-Sheet 5 IN VEN TORJ: Arlhur PJ/zepam Herberf J fngham ATTORNE'YJ 1945' A. P. SHEPARD ETAL METAL SPRAY GUNS OF THE WIRE FEED TYPE Filed Dec. 1, 1941 9 Sheets-Sheet 6 IN NTOR-S- Arthur Shepard gel-bar! 5, [1232mm am; 6L

ATTORNEY 1945- A. P. SHEPARD ETAL METAL SPRAY GUNS OF THE WIRE FEED TYPE Filed Dec.

2% N m MR. l MR, 5 1 -61 H mm mm 8M 9 En wk NE m I .3 J Em Sw w E I mom in m mum 8m N aw NR mum mm 8 man A 3w uh EN 3 NQNV MSW Mm \fiw m\ E INVENTORJ Arfbur P J/repa'm Herberi J lug/2am a .B Y

A TTORNEYJ Aug. 14, 1945. A. P. SHEPARD ETAL 2,331,931

METAL SPRAY GUNS OF THE WIRE FEED TYPE Filed Dec. 1, 1921 9 Sheets-Sheet 8 BY v A TTORNE Y-S g- 1945 A. P. SHEPARD ETAL 2,331,931

METAL SPRAY GUNS OF THE WIRE FEED TYPE Filed Dec. 1, 1941 9 Sheets-Sheet 9 Patented Aug. 14, 1945 UNITED STATES PATENT OFFICE METAL SPRAY GUN OF THE WIRE FEED TYPE Application December 1, 1941, Serial No. 421,194

'7 Claims.

This invention relates to new and useful improvements in metal spray guns of the wire feed type.

Metal spray guns of the wire feed type are devices in which a metal rod or wire is continuously fed into a melting zone, from which zone the metal is propelled in finely subdivided form by suitable means such as a blast of air or other gas. The rod or wire is fed into the melting zone by suitable rod or wire feeding means, such as knurled burs pressing against opposite sides of the wire. These wire or rod feeding means are driven, preferably operating through reduction gears, by a compressed gas motor, i. e., a motor, the rotor of which is rotated by the force of compressed gas. The load on the motor varies from time to time due to the changes in the position of the operator, kinks in the wire, etc. Since it is essential for successful spraying operations that the ratio of feed of the wire be uniformly maintained, it is likewise essential that the motor have a comparatively stable speed of operation, i. e., that its speed of operation be affected as little as possible by variations in the load. One common form of compressed gas motor is a compressed gas turbine and our invention shall be hereinafter described by way of illustration but not of limitation in connection with metal spray gun constructions of the wire feed gas blast type having a compressed gas turbine.

In the operation of metal spray guns, it is necessary to maintain difierent rates of feed when spraying difierent metals. For example, low melting point metals may be fed and sprayed more rapidly than higher melting point metals and larger diameter wires must be fed and sprayed more slowly than smaller diameter wires of the same material.

It is the usual practice to attempt the approximation of the roper conditions for the particular metal to be sprayed by providing for replaceable gearing designed to permit the gun to be operated at the required rate of wire feed and to permit the turbine to operate within a range of stable operation. Changing the gearing, however, involves loss of time and the possibility that metal particles will be picked up by the gears in handling and interfere with the operation of the gun. When attempting to eliminate gear changes by reducing the turbine speed through a throttling of the blast gas supply, the turbine becomes unstable and a uniform wire feed is no longer maintained as the then available power is insufficient to compensate for load increases. This operating instability of the ordinary gas blast operated turbine particularly at lower speeds, has been a serious disadvantage in metal spray gun constructions hitherto used. Although it may be possible in a given case to maintain a satisfactory wire feed, the ordinary gas turbine is very susceptible to variations in the operating load. The ordinary gas turbine has sufficient power for feeding the wire under normal conditions as long as a sufficient quantity of gas is supplied to the turbine rotor at a suiiiciently high pressure. The power requirements of the turbine, however, necessitate the feeding thereto of sufficient impelling gas to cause the turbine to operate at a very high speed. At whatever speed, however, the turbine operates with a given inflow and pressure of gas, all the power is used up and no excess power is available to take care of variations in the operating load.

One of the main problems in the past in attempting to govern the speed of gas blast type metal spray guns resides in the fact that the rotor of the gun must be governed accurately with a sensitive speed governor allowing for variations in speed at which it must be governed over a wide range of operating speeds. For instance, the speed range for the active operation of one particular gun of this type may be from 6,000 revolutions per minute R. P. S.) to almost 40,000 revolutions per minute (666 R. P. S.) This is a speed increase from lowest to highest usable speed of over 500%. With any governor utilizing centrifugal force, this condition presents a particularly acute problem because of the fact that centrifugal force varies as the square of the rotating speed. This means that if the ordinary centrifugal governor were added to the rotor of a metallizing gun, which operates through a 6 times speed range, the force operating on the governor weights would vary 36 times from lowest to highest speed and a mechanical movement actuating the governor mechanism would be subject to equally great variations so that it is in such case practically impossible to obtain the necessary sensitivity at each and every speed throughout the range. In a specific case, for instance, if the total movement of the governing mechanism, which controls the speed, is .150" between lowest and highest operating speed of the gun and if, a change from low speed to one-tenth higher speed produces a movement of .075" of the governing mechanism then the remaining nine-tenths of the speed range could only actuate the mechanism through a total movement of .075" which is the remaining distance. This would be an insufiicient movement of the mechanism for so wide a speed range, and the governor would not be sensitive. nor perform satisfactorily.

The governor construction in accordance with our invention makes it possible for the first time to utilize a governor of the centrifugal type to govern the rotor of a metal spray gun or the wire feed type through a wide speed range whereby the governing action, 1. e., the mechanical movement of the actuating mechanism is substantially approximately proportional to the change in speed of the rotor throughout the speed range covered by the governor.

The principle of the invention will be more fully understood from the diagrammatic representation and derivation (Fig. 22) developing governor weight positions for given speeds of rotation and balanced by appropriate spring resistance at such positions. In the diagram Y is the axis of rotation of a governor element having an arm of the length l and carrying at its end the mass M and pivotally connected at X. R is the distance of M from the axis oi rotation Y, and o the angle of deflection or the arm I from the axis of rotation Y.

When the governor element rotates at an angular velocity u about its axis Y, centrifugal force acts on the mass M in a direction perpendicular to the axis Y. This force is indicated by the vector arrow F. The force F can be considered to be resolved into a component force indicated by the vector arrow C, Perpendicular to the arm I, and a component force indicated by the vector arrow S, in the direction of the arm 1. The component force C tends to deflect the arm l and. assuming the latter to move outwardly against a spring resistance, indicated by the vector arrow P, is balanced by the spring resistance P at any given operating position of I. This spring resistance P is defined by Kc in which K is the unit spring force in dynes for unit angular deflection cl 1, i. e., for each degree of deflection of I, through a given range of deflection or corresponding value of o.

F=Mw'R '1 is the time required for may be expressed in R. P. S.

one revolution and As C is balanced by the spring resistance of arm Z.

(o may be expressed in radians or degrees 11' K is appropriately chosen.)

Assuming as a representative example an opcrating range of from 6000 to 40,000 R. P. M. to 666 R. P. S.) and a total maximum deflection oi? 88 at a maximum speed 01' 666 R. P. 8., the value of K for equilibrium at that deflection may be found by inserting the various values in Equation 12 resolved for K.

t 2 o 21r 6668; 176 :883-7 Table I [Deflection range 0-88] When plotting the curve defined by Equation 12 in accordance with the values given in Table I the curve has a slope as demonstrated by curve I in Fig. I.

When using instead of an arm controlled by a spring force acting throughout the entire range of 0 to 88, an arm controlled by a spring force acting through a range beginning with a predetermined initial position at the angle v of the arm I with respect to the axis of rotation Y, a diiierent value for K controls. This value is defined by Equation 13 except that the value for =(88'y) 21rR.P.S. sin 2(88 W The values of K obtained for different values of 'y are listed in the following Table A.

Table A The R. P. S. values in accordance with Equation 14 for predetermined angles of '7 are determined The R. P. S. values for difierent values of and for each series with constant predetermined values for 'y and corresponding constant values for K are listed in the following Tables II, III, IV, V, and VI.

Table III [Deflection range 7 to 88] R. P. S 32. 56 109. 41 179. 6 309.8 461.2 666 Table IV [Deflection range 1 to 88} R.P.S 0 40.7 147.9 286.8 450.0 666 Table V [Deflection range 7 to 88] R.P.S 0 59.6 147.9 252.9 434.8 666 Table VI [Deflection range 7 to 88] R.P.S 0 80.3 210.5 417.7 666 The curves plotted for each series of values for and R. P. 8., given in the foregoing tables, are illustrated in Fig. 21 as II, III, IV, V and VI corresponding respectively to the tables of the same designation.

Analyzing these curves, it will be seen that in each curve there is a section or sections the slope of which roughly approximates a constant, i. e.. for approximately equal increments in R. P. S. there are approximately uniform increments in angular deflection of the arm Z. This permits the speed governing mechanism to be variably adjusted to any desired R. P. S. throughout the R. P. S. range defined by the particular constant slope curve section and to thereby attain an approximately accurate, uniform and sensitive speed governing operation.

It will be seen however that the different constant slope curve sections of the various curves difler in the R. P. S. range covered by such curve sections. Thus, for instance, the section of curve I between 10 and 70 angular deflection, though roughly approximating a constant in its slope, has a very steep pitch with respect to the abscissa and covers for a total of 60 deflection an R. P. S. range of only from 115 to 220 R. P. S. that is a total R. P. S. range of only 105 R. P. S. As to the curve sections of curve I between 70 and 85 angular deflection and 80 and 88 angular deflection, the pitch with respect to the abscissa of these sections is not as steep. As to the section between 70 and 85 angular deflection of curve I, there is an R. P. S. range of 220 to about 465, i. e., a total R. P. S. range of only 245 R. P. S. for a total deflection of With respect to the section of curve I between 80 and 88 angular deflection, the R. P. S. range is from 330 to 666 Or a total of only 333 R. P. S. for 8 deflection.

It is thus seen from the analysis of curve I that there is no single constant slope section in this curve defining anywhere an R. P. S. range covering in excess of 200% speed variations. Though a governor element operating within the range defined by curve I may be used within the limitations inherent therein, such governor element is ordinarily not satisfactory in the case of a metal spray gun of the wire feed type normally operating within a speed range where the maximum operating range is in excess of 200% of the minimum operating range.

The dotted outlines of the various curves represent the plotted slopes below minimum operating R. P. S., i. e., 100 R. P. S. of the device exemplified in this illustration.

Analyzing the curves based on a predetermined initial angular position of the arm l (curves II, III, IV, V, and VI) it will be seen that curves II and III also do not possess any section above minimum operating R. P. S. of 100 for which the slope roughly approximates a constant and which defines an R. P. S. range covering in excess of 200% speed variation. In curves IV, V, and VI, it will be seen that these curves roughly approximate a constant all the way between the minimum operating R. P. S. of 100 and the maximum operating R. P. S. of 666 which is equivalent to an R. P. S. range covering in excess of 500% speed variation. In these cases the approximation of a constant increases with the increase in the predetermined initial angular position of the arm with respect to the axis of rotation and, although for practical operation a predetermined angle of 60, as exemplified by curve IV, will give satisfactory results, higher angles as illustrated by curves V and VI are preferred. Although the constancy of slope improves with higher initial angles, it has been found that the governing element with too high a predetermined initial angle may lose sensitivity. For best results an arm having its spring set for a predetermined initial angular position between 70 and and preferably at approximately 75 with respect to its axis or rotation is preferred. This is exemplified in its operating range by curve VI. "Initial position" or similar expression as used herein in connection with the arm or arms in accordance with our invention is intended to connote the angular position assumed by the arm or arms at zero speed.

Although in the foregoing equations and the various curves illustrated in Fig. 21 a minimum operating range of R. P. S. and a maximum operating range of 666 R. P. S. with an assumed maximum deflection of 88 have been selected, it is understood that these values are merely used by way of exemplification of the principles underlying our invention. The results are not substantially different and the same type of curves result if other values or ranges are substituted for those hereinabove used.

The above derivation shows a relationship between governor weight positions and speed at which equal increments in speed produce approximately equal increments in angular positions of the governor arm. It is now possible to combine a lever arm and weight structure, embodying this principle, with speed control means and with means for adjustably positioning such speed control means to produce a governor operating satisfactorily over a wide speed range.

In the actual operation of the governor there is a governing force acting to control the speed and in the illustrations shown in the drawings; this governing force is parallel to the axis of rotation. For a complete analysis of the forces involved during governing this governing force must be taken into account a well as the centrifugal force and spring force.

The variable speed governing mechanism, in accordance with the invention, for a metal spray gun construction of the wire feed type, having a compressed gas motor, comprises at least one arm, rotatable with the rotor of such motor and centrifugally deflectable for angular deflection with respect to its axis of rotation, against spring resistance, from a predetermined initial position, preferably of at least 60, with respect to such axis; speed control means, composed of at least one first and one second element, the first element being positioned and adapted to be operatively acted upon by the arm or arms upon centrifugal actuation of the arm or arms to cooperate, by mechanical movement, with the second element to thereby eiiect speed control of the rotor; and means for variably adjusting the relative position between the second element and the initial position of the first element within a range of mechanical movement of the first element defined by angular deflection of the arm between minimum and maximum operating speeds of the rotor. The initial position of the first element of the speed control means referred to herein, designates that position of such first element as is controlled by the deflectable arm or arms at its or their initial position.

The metal spray gun of the wire feed type embodying our invention does not require any change of gearing. The same is capable of maintaining any number of practical wire feeding speeds and may be shifted from one speed to another by a simple adjustment of the preferably manual control means. Furthermore, the motor or turbine of such metal spray gun is at all times maintained in a stable operating condition. The particular construction in accordance with our invention permits the use of these metal spray guns under substantially stable operating conditions, over a much wider range of wire feed speeds than was heretofore possible.

The invention will be more fully understood and further objects thereof will appear from the following description read in conjunction with the drawings in which:

Fig. 1 is a sideview of the metal spray gun illustrating one embodiment of a construction in accordance with the invention;

Fig. 2 is a vertical section through the construction shown in Fig. 1 on the plane indicated by IIII;

Fig. 3 is an illustration of the stopwasher as seen in the plane IIIIII of Fig. 2;

Fig. 4 is a vertical section through the construction shown in Fig. 1 on the plane indicated by IVIV;

Fig. 5 is a vertical section through the construction shown in Fig. 1 on the plane indicated by V-V except for the construction of the structure illustrated in Fig. 7 which is shown on the plane indicated by the section line VV' in Fig. 'l;

Fig. 6 illustrates a view of part of the section shown in Fig. 5;

Fig. 6A is a plan view of the interior of the construction shown in Fig. 6;

Fig. 6B is a view of one element of the construction shown in Fig. 5;

Fig. '7 is a side view of the rotor element of the pray gun;

Fig. 8 is a view of part of the construction shown in Fig. 7 at right angles thereto;

Fig. 9 is a central vertical section parallel to the construction shown in Fig. 1;

Fig. 10 is a vertical section through the construction shown in Fig. 5 on the plane indicated by X-X;

Fig. 11 is a sectional view of Fig. 5 in the plane indicated by IHXI;

.Fig. 12 is one of the governor elements in accordance with our invention;

Fig. 13 is a vertical section through the construction shown in Fig. 5 on the plane indicated by XIII-XIII;

Figs. 14, 15, and 16 illustrate sectional views of variations in the construction of a spray gun embodying our invention;

Fig. 17 is a sideview of part of a spray gun construction illustrating an alternative embodiment of our invention;

Fig. 18 is a vertical section through the construction shown in Fig. 17 on the plane indicated by XVIIIXVIII;

Fig. 19 is a section through a metal spray gun embodying a modification of the construction illustrated in Fig. 13;

Fig. 20 is a sideview of one element shown in the construction of Fig. 19;

Fig. 21 is a graphic representation of the principle underlying the invention and Fig. 22 is a diagrammatic representation for deriving governor weight positions.

The speed control means in accordance with our invention may be any suitable means for accomplishing that purpose. They may, for instance, comprise as is by way of example illustrated in connection with Figs. 1 to 16 inclusive 9. power absorption mechaniwalternatively comprise as is exemplified by gs. 1'? to 20 inclusive a control mechanism for the regulation of the compressed gas supply to the motor or turbine.

The arm in accordance with our invention operating against sprin resistance when centrifugally actuated may be any one or a multiple number of suitable spring force controlled arms though we prefer a construction where the arm or arms comprise a spring element such as for instance one or more spring arms, i. e., arms made of spring material, set at the desired predetermined initial angle.

In case of a substantially rigi arm, we prefer to obtain deflectibility thereof by pivotally mounting the arm with respect to its axis of rotation. Within the preferred embodiment of our invention however, when using one or more spring arms, pivotable mounting thereof may be dispensed with as a rule since these as such will usually permit satisfactory deflection.

Referring to the drawings, I (Fig. 2) indicates the inlet for oxygen or other combustion supporting gas, 2 the inlet for acetylene or other combustible gas, and 3 the inlet for air or other gas for atomization of the metal, projection of the metal spray and driving of the turbine. When plug 4 of valve 5' is in the position shown, each of the inlets registers with a corresponding hole in the plug, these holes being indicated by numerals 5, 6 and I respectively. In this position, oxygen flows through duct HI into duct II. The combustible gas flows through duct I! to mix with the oxygen in duct II and the air flows through duct l5 into chamber l6 and also flows through the side connection ll into turbine manifold l9. Openings 5, 6 and 1 in plug 4 are so arranged that as handle 8 is turned from the off position, which is at a right angle to the showing in Fig.

2, first some combustible gas passes into duct II and thence to the burner outlet to enable the burner to be lighted. Some air passes simultaneously into manifold l9 to enable the turbine to come up to speed. Alternatively, all th valve passages may be opened but at such rates of flow as to establish favorable lighting conditions which are different from the conditions obtaining when the gun is in operation. This position of the valve is called the lighting position. The washer 20 (Fig. 3) defines a hole 2| of rectangular crosssection which fits closely the shank 22 (or corresponding section) (Fig. 2) of the plug 4. The washer 20 is formed with the depression 23 (Fig. 3). This washer is spring pressed and this depression slips onto the head of pin 24 when handle 8 is in the correct position for lighting the burner. This offers sufficient resistance to indicate to the operator the lighting position. After the burner has been lighted a slight pressure against handle forces the depression 23 out of engagement with the head of the pin 24. A further movement of handle 0 causes oxygen to flow through duct I0 which establishes a melting flame with the ignited gas and the final movement of handle 8 to the position shown in Fig. 2 permits air to flow into duct l and thence into chamber I6 to proiect the sprayed metal upon the surface to be covered.

The construction of that part of the gun by which the rod or wire is melted and projected will be explained by reference to Fig. 9. The wire 31 moves forward to guide 3| and through duct 32 to the interior 33 of the burner tip 34. The mixture of air and oxygen move forward through the duct II, which is immediately behind duct 32 (the arrangement is shown in Fig. 2) and into the annular space 35. From this annular space 35 the combustible mixture moves forward through a number of holes to be discharged through convergent orifices 35 against the wire. This forms a zone of gases undergoing combustion, whereby the wire 31 melts as rapidly as it is progressively advanced into the zone, for which reason this zone is referred to as a melting zone. The air from the chamber I0 advances through the annular space 40 surrounding burner tip 34 and is projected by air nozzle 4| in such a way as to sub-divide and propel the molten metal. The air tip 4| is threaded to the outer shell 42 of the burner so that the orifice 43 defined by conical interior of air tip 4| and conical exterior of burner tip 34 may be adjusted with corresponding variations in the characteristics of the air blast. When a satisfactory adjustment has been made, the tip 4| is locked in position by the lock nut 44. It will be noted that the air in passing forward from the chamber l6 goes through the constricted annular space 45 which exerts a definite control over the volume of air passing. As a result of this construction and the orifice efiect thereby created, the adjustment of air tip 4| modifies the characteristics of the air blast without so great a modification of the volume of air passing thereto as would otherwise result, which is decidedly advantageous in the adjustment and operation of the gun.

The wire 31 (Fig. 9) enters the gun through the annular guide 50 of hardened material in which is the duct 5|. The upper and lower surfaces of the wire are engaged respectively by the burs 52 and 53. Bur 53 is carried by shaft 54, which shaft is driven by an air turbine through suitable intermediate gearing which will be hereinafter described. Shaft 54 (Fig. 4) also drives the gear 55 in mesh with gear 56, which in turn drives the upper bur 52. Both gear 58 and bur 52 are secured to the tubular member 51 which rotates on the spool 58 carried by pin 50 (Fig. 4). The screw 59 lS-T'Cfil'lled by the saddle 00 and this saddle is pivotally secured (Fig. 9) to frame SI of the gun by the hinge 62. When cap 65 is turned the threaded end 06 of the screw 81 advances into the threaded member 53 which is a part of frame GI and the spring I0 exerts pressure on the saddle 80, thereby forcing the upper bur 5.: toward the lower bur 53 and thereby causing the burs to engage and advance the wire 31. Conversely, when cap 65 is turned in the reverse direction, pressure of spring I0 on saddle 60 is released and the burs move freely without engaging and advancing the wire.

The shaft 54 (Fig. 4) which drives bur 53 is mounted in ball-bearings I0 and II. Bearing I0 is held in frame GI and bearing II is held in the housing I2 which is attached to frame 6|. The shaft 54 is driven by the worm gear 13, which in turn is driven by the worm I4, carried by the shaft 15. Shaft I5 (Fig. 10) is carried by ballbearings I5 and I1 mounted in the housing 12. Shaft I5 is in turn driven through the worm gear I0 by the worm I9. The worm I9 (Fig. 5) is integral with the shaft carried by bearings 35 and 86. Bearing 85 is mounted in housing 12 and bearing 06 is mounted in the cap or cover of the turbine 9|.

Turbine 9I (Fig. 5) includes the turbine rotor drum secured to shaft 80. Details of the blading I00 are apparent from Figs. 7 and 8. As evident from Fig. 6, cover 90 includes the mounting |0| for the ball-bearing 05 and three ridges I02 (Figs. 6 and 6A) radially arranged about mounting |0I on the interior surface of the cover. The washer-shaped member I03 is made of fine wire mesh and rests directly upon ridges I02. The washer I04 rests directly on the washer I03. The washer I04 defines the perforations I05 (Fig. 6A) The washers I03 and I04 are held in contact with each other and with the ridges I02 by the strips I06, which in turn are secured to the ridges I02 by the screws I01. One result of this construction is that the exhaust from the turbine flows through perforations I05 in the washer I04, thence through the openings in the fine screen of which washer I03 is composed, and thence through exhaust ports 0, in cover 90 (Fig. 6 and Fig. 1) thereby resulting in more quiet operation of the turbine.

The nozzle arrangement operating the turbine is shown in Fig. 11. Face 5 together with the housing 90 defines the space in which the turbine drum rotates; (the drum is not shown to facilitate inspection of the nozzle structure). A nozzle I30 is permanently connected to the manifold I3. Hence, part of the air or other gas which enters through connection 3 and into manifold I9 can flow through Jet and hence propel the turbine. All of these connections are made large enough to propel the turbine at the maximum speed at which it will be required to operate, and hence an excessive amount of gas is supplied for every speed except the maximum.

Specifically referring to Figs. 5, 6, 6A, 6B, 7, 8, l2, and 13, illustrating an embodiment of a centrifugally operated power absorption governor in accordance with the invention, rotor 95 carries governor spring element 200 mounted thereon by means of screws -20|. This spring element is set with respect to the axis of shaft 80 at an angle of approximately 75. The weights 202 in this case consist of screws clamped through a hole in each end of the spring 200 by the nuts 200.

When the rotor 95 is at rest, the weights 202 take the position shown. When the rotor 95 rotates, the centrifugal force acting on the weights 202 tends to pull them away from the axis of the shaft and in so doing tends to deflect the arms of the spring 200 forwardly towards a perpendicular position to the axis of shaft 90. Thi tendency of the springs to straighten under the centrifugal force acting on the weights is increased by the weight of nuts 203, which, because they extend beyond the bent spring, exert a twisting force due to the action of centrifugal force which twisting force is also in the direction to deflect the spring arm 200 nearly perpendicular to the axis of shaft 80. When the rotor 95 is operating at the lower end of its speed range, the spring arms 200 are but slightly deflected from their initial position. In this speed range a slight change of speed causes a motion of the buttons or weights essentially in the direction of axis of shaft 00, due to the change in the amount of centrifugal force acting on weight 202 and nuts 203. The deflection of the spring is not proportional to the square of the speed of rotation but is approximately directly proportional to the speed of rotation. As the speed increases and the buttons 202 move approximately parallel to the axis of shaft 80. they deflect the spring arms 200 to a position more nearly perpendicular to the axis of shaft 80. The buttons 202 therefore operate in and out essentially parallel to the axis of shaft throughout the entire large speed range required for a metallizing gun, and the position of the buttons 202 at any speed represents a measore of that speed.

Slidably mounted on shaft 80 is brake disc subassembly 204. This sub-assembly consists of hub 205, disc 200 and bent clip 201. Bent clip 201 and disc 205 are mounted on hub 205 and secured thereto by screws 208. The ends of the arms of the piece 201 are bent up to form ears or prongs 209. As assembled these ears 209 fit on either side of each weight button 202, hence, as rotor 95 rotates, brake disc sub-assembly 204 also rotates being driven by the contact of weight buttons 202 with ears 209 of spring clip 201. Mounted on shaft 80 next to bearing 06 is washer 2l0. Nut 2 II which screws on to threaded end of shaft 80 clamps bearing 06 and washer 210 against the shoulder of the shaft 00. Assembled between washer 2H! and the hub 205 is the compression coil spring 2I2. This coil spring 2l2 normally tends to hold the brake disc sub-assembly 204 towards the rotor 95, so that the weight buttons 202 contact the ends of spring clip 201.

In operation, as the rotor 95 speeds up, the weight buttons 202 move parallel to the axis of shaft 90 towards the brake disc sub-assembly 204, and by the contact of the buttons 202 with the spring clip 201 force the brake disc sub-assembly 204 to slide along the shaft 00 in opposition to the coil spring H2. The turbine housing 90 is cut away at three sections 213, so as to permit the three segments 2 of spider or friction ring 2 l to fit loosely through the resulting openings. The outer periphery of the three segments 2, of spider 2l5 are threaded. Ring nut 215, substantially forming an extension of the turbine housing 90, is threaded in its bore to engage the threads of spider Hi. This thread extends on the bore of ring nut 2l5 to a neck at the end of the thread which is terminated by shoulder 2".

When the nut H5 is turned the spider 2l5 travels in and out on the thread and is stopped at one end of its travel by shoulder 2H, and at the other end of its travel by forcing brake disc sub-assembly 204 to the limit of its travel towards the rotor 95. Ring nut 2 l 6 is rotatably mounted on housing 90 and is located by bearing surface 2 l 8. Disc 219 is secured to housing 00 by screws 220, and acts to restrain the ring nut 2l0 on the housing 90 between the housing shoulder 22! and itself so that the ring nut 2l5 is free to rotate but cannot move longitudinally. Ring nut 2l8 is provided with grooves 222 and 223, which extend around its faces and which are packed with a packing material such as cork or graphite-impregnated cotton string. This construction serves the double purpose of keeping dirt out of the mechanism and also of providing a necessary amount of friction so that ring nut 216 will not turn accidentally. A section of the outer periphery of ring nut 215 is knurled at 224 to provide an easy grip to the fingers for turning. As that portion of the housing 90 which has not been cut away to allow space for the spider segments 2l4 straddles these segments of the spider 2l5, the spider H5 is not permitted to rotate, but is permitted to move parallel to the axisof shaft 00. By screwing the ring nut 216 one way or the other the spider 2l5 may be located longitudinally in any desired position within the limits of its motion. The ring shaped face 225 of spider 2 l 5 (Fig. 63) represents a braking surface to contact the face of the brake disc 206. Brake disc 205 is preferably made of hardened steel and polished on its contacting surface. The braking surface 225 of spider 2| 5 is preferably made of sprayed metal, most preferably of sprayed bronze. For smooth operation it is important that the coefllcient of friction, between these two surfaces remain as constant as possible throughout varying conditions of service, as well as throughout varying conditions of lubrication. Sprayed metal is particularly adapted for this purpose because of its constant coefficient of friction and because due to its porosity it will absorb lubricant and hence operate under at least semilubricated conditions when it might otherwise be operating dry. The braking face 225 may be divided into segments if desired by cutting a number of radial shallow slots 228. Such slots 226 will tend to collect foreign matter and prevent scratching of the braking surface. Shaft is provided with lubricant holes 221 and 228, which extend from the lubricant chamber 229 behind the bearing to the surface of the shaft beneath hub 205. Housing is provided with the grease plug 290 which may be removed for the introduction of grease to chamber 229 and to the holes in the shaft 221, 229 to the sliding bearing surface between shaft 00 and hub 205. As grease is added through chamber 229, a small amount of grease will leak past bearing 05 and washer .210 and be thrown upwards by the rotating washer M0 in such a direction that some of the grease will locate on the threads of ring nut 2|5 and some of the grease will locate on the inner periphery of spider 2I5 and find its way to the bearing surface 225. Hence, the whole governor mechanism may be lubricated, as well as the bearing 05 by the introduction of grease into chamber 220.

Bent clip 201 performs the double function, first of providing a driving means through the ears 209, the buttons 202, the spring 200 and the rotor 96 between the rotor and the brake disc sub-assembly 204. The other function is that of absorbing by its resiliency the pounding action of weight buttons 202. When operating at high speeds, there is a natural tendency for the weight buttons 202 which are mounted on the ends of spring arms 200 to enter into a vibratory motion. This motion is quickly absorbed by the resiliency of the arms of bent clip 201. It will be understood that bent clip 201 may be eliminated from the sub-assembly 204 and that the weight buttons 202 may then be made to bear directly against brake disc 206. If bent clip 201 is eliminated, however, some other means such as keying, gearing or other drive connection should be used to drive brake disc sub-assembly 204 and cause it to rotate with rotor 35. When bent clip 201 is used, the brake disc 265 may be made lighter than would otherwise be possible, as piece 201 also serves to apply thrust load from the weight buttons 202 more nearly at the center of disc 203, hence minimizing the distortion due to an unevenly applied load.

In operation ring nut H6 is turned to locate spider 215 in any desired position corresponding to a desired speed. As a full volume of air under full pressure is provided at all times to the turbine rotor 95, this rotor will tend to increase its speed, causing the weight buttons 202 to move toward brake disc sub-assembly 204 and cause the brake disc sub-assembly to move toward the friction surface 225 of spider 2 l5. As the desired speed is reached the brake disc 206 brushes against friction surface 225, generating heat by friction, thus absorbing any excess power which may be developed by the turbine rotor 35. Any heat which is thus developed is absorbed and carried away by the exhaust gas from the turbine which must pass around the spider 2|5 before finally exhausting through ports I I0. The speed of the rotor 95 is, therefore, accurately established by the position of the spider 2l5, for if the rotor 35 tends to travel faster, increased pressure is exerted between brake disc 206 and braking surface 225, causing an increase in friction. If due to a kink or bend in wire 31 or some other cause an increased load is imposed on the driving mechanism of the metallizing gun, this load causes the rotor 95 to slow down very slightly. However, even a very slight reduction in speed is sufficient to cause the weight buttons 202 to move slightly away from the brake disc sub-assembly 204 and hence release the pressure between the friction surfaces 206 and 225. As this pressure is released less friction occurs and less heat is generated and hence an extra amount of power is released for active use of the turbine and driving mechanism, and hence no further reduction in speed occurs. On the other hand, if the load on the driving mechanism reduces suddenly or even gradually, the rotor 95 tends to speed up very slightly. Even a slight increase in speed is sufiioient to cause this sub-assembly to press harder against the friction surface 225, which results in a greater amount of power being absorbed by friction; hence, only a very slight increase in speed is possible even though the load on the driving mechanism would be released entirely. The action of the governor is practically instantaneous so that a very steady wire feed drive is provided, which can easily be adjusted to any given speed over a wide range of speeds by the simple expedient of turning ring nut 2l6. This constancy of wire feed is maintained even with variations in the amount or pressure of the blast gas supplied for the operation of the turbine.

The construction shown in Fig. 14 is similar to that described above, except that brake disc sub-assembly 204 has been eliminated. In this construction weight buttons 202' operate the same as previously described, except that as they move parallel to the axis of shaft 30' under the action of centrifugal force, they are caused to contact directly with thefriction surface 225 of spider 2l5'. With this construction the friction surface 225' is smooth and continuous and is not slotted as at 226 in the previously described construction. Friction in this case is produced directly between the action of weight buttons 202 and friction surface 225 but the adjustments in operation are otherwise the same as previously described.

In the construction shown in Fig. 15 the rotor spring and weight button construction and the brake disc sub-assembly construction are the same as that described in connection with Fig. 5. In this construction, however, the turbine housing 90" is not cut away as at 2I3 (Fig. 13) as no spider nor ring nut is used. Instead, screw 23l is provided to operate through a threaded hole 232 in housing 90". The outer end of screw 23l is provided with a knurled knob 233 and at the inner end with a small disc 234 which is faced with friction material 235, preferably made of sprayed metal. The operation is the same as that described in connection with Fig. 5 except that as the rotor speeds up, brake disc subassembly 204" is forced to contact friction surface 235 until sufficient friction is generated and absorbed to permit the turbine to arrive at and maintain its pro-determined speed. In this case, the speed is pre-determined or adjusted by the location of friction surface 235 which is obtained by screwing the screw 23l in or out by means of the knurled knob 233.

The construction shown in Fig. 16 is similar to the construction described in connection with Fig. 5 except that brake disc assembly 204 (of Fig. 5) has been replaced by friction button sub-assembly 235. This assembly consists of a hub 231, slidably mounted on shaft and a bent clip 238 similar to bent clip 201, of Fig. 5, which is secured to hub 231 by screws 239. Ears 240 are provided at the ends of bent clip 238 for the same purpose as described in connection with bent clip 201 of Fig. 5. On each end of bent clip 238 is mounted a friction button 24l. As the turbine speeds up, clip sub-assembly 236 is moved along shaft 30 as described in connection with subassembly 204 in Fig. 5. Buttons 24l hence con tact friction surface 225" of spider 2l5' and produce sufficient friction to cause the turbine to operate at a predetermined speed. The control and operation of the mechanism with this construction is the same as that shown in connection with the construction of Fig. 5, as the friction button sub-assembly 236 replaces the friction disc sub-assembly 204 of Fig. 5.

Specifically referring to the alternative construction in accordance with our invention as exemplified in Figs. 1'1 to 20 inclusive, sliding hub GM is provided with a pin 300 which extends radially through it.

Shaft 602 has a slot 3!" which is wide enough to permit space for pin 300 and which is long enough, parallel to the axis of the shaft, to permit considerably longitudinal movement of hub 6M, along the shaft when pin 300 is in place extending through the slot 30!. Hole 302 is centrally located in shaft 602 and extends from its end past slot 30I. Located in hole 302 is pin 303 which is fitted as to be freely slidable in hole 302. One end of pin 303 extends beyond the end of shaft 002 and is smooth and rounded oil on this extending end. Valve plunger 304 is slidably mounted in housing 603 and is forced in the direction toward the shaft 602 by the action of coil spring 305 which acts against pin 306 in one end of valve plunger 304. Threadedly mounted in housing 003 is valve body 301 which has threads 300 and finger wheel 300 and valve seat 3l0. Nut 3 holds packing material 3I2 against the thread 308 to prevent leakage of air around the threads. Air passage M3 is provided and leads from the air duct I9 to the space 3 between the valve body 301 and the housing 603. Hole 3|5 through the side of the valve body 301 permits passage of air from space 3I4 to space 316. When valve plunger 304 is not in contact with valve seat 3|0 air can pass from chamber 3H5 into chamber 3|! which surrounds the end of the valve plunger 304. Air passage 3! connects space 3 with the short duct BIS. Turbine air jet 604 extends from short duct 3 l to the surface of housing 605 at such an angle that air emer ing from jet 604 impinges against turbine blades I00 to cause turbine rotor 95 to rotate.

In operation the supply of air for operating the turbine enters through duct l9 as previously described. From duct IS the air flows through passage 3l3 into space 3I4, through hole 3l5 into space 3 I 5. From space 3l6 the air passes between the valve seat 3l0 and the face of the valve plunger 304 into the space 3II.. Thence it goes through the passage 3|8 into the short duct 3I9 and emerges through turbine jet 604 causing turbine rotor 95 to rotate. As turbine rotor 05 increases in speed, the governor Weight buttons 202 move out approximately parallel to the axis of shaft 002 in a direction away from the turbine rotor 95. These buttons 202 which contact the ends of spring clip cause hub 60I to move along the shaft 602 in a direction away from the rotor 35. As pin 300 travels along the shaft with the hub G0l it forces pin 303 to press against the end of valve plunger 304 causing valve plunger 304 to approach valve seat 3 I 0. As valve plunger 304 approaches valve seat M0 the air supplied to jet 004 is restricted thus reducing the energy supplied to turbine rotor 05. Consequently at a predetermined speed the air flow will be sufficiently restricted to prevent a further increase of the speed of turbine rotor 95 and the rotor will operate at this predetermined speed. The operating speed of rotor 35 is predetermined or selected either in advance or during operation by turning the thumb wheel 30!! of valve body 301. This screws the valve body 301 in and out on the thread 308 causing the valve seat 310 to get closer to or farther from the face of valve plunger 304. When more speed is desired the valve body is turned in a direction to provide more space between the seat and plunger and when it is desired to reduce the speed it is turned in the opposite direction thus providing less space between the valve seat and valve plunger.

Once the speed has been predetermined by the adjustment of thumb wheel 309 the rotor 95 will maintain a speed which is nearly constant. If for any reason an increase of load should be applied to the mechanism, as for instance by a kink in the wire being fed then at first the speed of rotor 95 will be slightly reduced. After a very slight reduction in speed, however, the governor weight buttons 202 will move slightly toward the rotor permitting spring 2 to force hub 60l along shaft 602 toward rotor 95. This permits pin 303 to move back and hence spring 305 will move plunger 304 away from valve seat 0. This will permit more air to flow between the valve seat and the plunger and through the passage 3! and 3l9 to the jet 004. Hence more power is supplied to the rotor to overcome the increase in load and prevent further reduction in speed. Only a very slight reduction in speed is necessary to cause the governor to operate. The end of valve plunger 304 is made relatively large and the passage 3H5 in the valve seat is made relatively large so that a very slight lateral movement of the plunger 304 is sufficient to cause a large adjustment in the amount of air which can pass between the valve seat and the plunger. Only a very small motion of the governor weight 202 is required to provide a relatively large additional amount of energy in the form of air energy to act on turbine rotor 05. If for any reason the load on the operating mechanism should suddenly become less, then the turbine rotor would speed up slightly. However, even a relatively slight increase in speed will be sufllcient to cause the governor weights 202 to move against the spring clip 201 causing the hub GM and pin 300 to move away from the rotor 05 and cause pin 303 to press against the end of valve plunger 304 pressing it closer to valve seat 3l0. This action would restrict the flow of air to jet 304 and to the turbine rotor 35 and hence prevent further increase in speed. This construction allows for an ample potential supply of energy to the rotor and also prevents any tendency of the rotor to overspeed or run away.

An alternative construction is shown in the illustrations in Figures 19 and 20. In this embodiment of our invention the governor spring 200 and governor weights 500 are assembled in the same manner as previously described but they are mounted on the reverse side of the rotor so that in the illustration in Fig. 19, the governor spring 200 is mounted on the rotor 05' on the side toward the housing 605'. In this case no sliding hub or spring clip are required. Disc 400 is mounted close to and parallel to the face of housing 005'. At the center of disc 400 a short hub is provided which is pressed into the center of ball bearing 40L The outside race of bearing 40| is pressed into the housing 605' so that disc 400 can rotate freely about the same axis as that of shaft 602'. A slot 402 is provided in disc 400, as illustrated in Figs. 19 and 20. Fitted into the face of housing 605 is small pin 403. This pin limits the rotary motion of disc 400 to a motion through a small angle so that at each end of this small permissible amount of motion, the motion is arrested by contact of one or the other end of slot 402 against pin 403. A circular groove 404 is provided in the face of housing 005 to provide space for flat coil spring 405. One end of coil spring 405 is bent at right angles to the plane of the spring at 406 and fits into a hole in the housing 605 at the bottom of the groove 404. The other end 401 of flat coil spring 405 is bent at right angles in the opposite direction and fits through a hole provided for it in the disc 400. This spring is so wound as to act between the housing 505' and the disc 400 so as to tend to force it as far as it will go in a counterclockwise direction as viewed in Fig. 20. Slot 402 is cut wide enough so that the disc 400 does not cover the opening of airjet 004' when disc 400 has been forced by spring 405 to the limit of its travel in a counterclockwise direction (Fig. 20). The location of pin 403 with respect to the location of the opening of Jet 304' and the length of slot 102 are such that when the disc 400 has been forced in a clockwise direction as far as it will go that part of the disc 400 indicated at 408 will cover up the opening of the Jet 8M.

Bearing H which is mounted on one end of shaft 602' is slidably fitted in housing I2 and housing 12' i made sufiiciently long to permit of a considerable longitudinal motion of shaft 602'. At the other end of shaft 602', bearing 86' is clamped to the shaft by nut 409 and is clamped in a housing 4 III by the threaded cap 4| l. The outside of housing M is provided with threads 4|! which mate with threads in housing 603'; on the end of bearing housing 410, a thumb wheel 3 is provided. If thumb wheel I I3 is turned, the housing M0 is screwed either in or out of the housing 603'; and as the bearing 86' is rigidly clamped in the housing 4 l 0 and to the shaft 602' the shaft and the whole rotor assembly are forced either in or out. Hence by turning thumb wheel 3 it is possible to adjust the longitudinal position of shaft 602' and the whole rotor assembly including rotor 95', governor spring 200 and governor weight button 500. The governor weight buttons 500 are made of a sufficient length so that they can contact the face of disc llill.

In operation air is supplied to turbine jet 604' as previously described and emerges from the jet acts on turbine rotor blades lllll' causing the turbine rotor 95' to rotate. As the turbine rotor 95' increases in speed the weight buttons 500 tend to move parallel to the axis of shaft 602' in a direction towards the face of disc It. When the weight buttons 500 contact the face of disc 400, and exert even a slight pressure against the disc, they cause friction between the disc and themselves and hence, tend to rotate disc 400, The direction in which they tend to rotate the disc 400 is clockwise as viewed in Fig. 20 and the friction of the weight buttons 500 against disc 400 tends to rotate it in opposition to flat coil spring 405. As the speed of rotor 95' increases this rotary frictional force exerted by the weight buttons 500 on disc 400 becomes sufficient to overcome the force of spring 405 and cause the disc 400 to rotate through a slight angle until part 408 of the disc at least partially obstructs the opening of air jet 804'. This obstruction of the air let by the interposition of part 408 of disc 40!) between jet 804' and the turbine roto blades Hill reduces the air energy supplied to the turbine rotor 95' and no further increase of speed is possible, the turbine rotor 95' arriving at and maintaining a, predetermined speed. This speed is predetermined, or, may be adjusted during operation by an adjustment of the longitudinal position of the rotor assembly which is effected by screwing the thumb nut l l 3 either in or out. If more speed is desired the thumb nut 3 will be turned in such a direction as to screw the rotor assembly away from the face of disc 400 and if less speed is required it will be turned in the opposite direction. The farther removed the rotor assembly is from disc 400 the greater speed will have to be attained before the deflection of the spring 200 will be sufficient to permit the governor weight button 500 to contact and thus rotate disc lllll.

Once a speed adjustment has been made the turbine rotor 95' will maintain its predetermined speed with but slight variations. If for some reasons such as a kink in the wire being fed through me metal spray gun an increased load is imposed upon the turbine rotor 95' then it will slow down slightly. As soon as it slows down even a very small amount, the weight buttons son will move away from the disc 400; if they do not actually move away from disc "0 they will at least reduce the pressure which they exert against the disc 40 so as to produce less obstruction of the air jet 604'. Hence more energy is supplied to turbine rotor 55' to overcome the additional load which was imposed, and no further reduction of speed will occur. If on the other hand, for any reason, less load is imposed on rotor 95', the same will speed up slightly but even the slightest increase in speed will be sufficient to cause governor weight buttons 500 to bear more heavily against the face of disc 400, producing more friction which tends to rotate disc 40a in such a direction as to further obstruct the opening of air jet 604'. As this will reduce the amount of energy available for the turbine rotor no further increase in speed is possible.

Although the foregoing description is complete as far as the action of the governor on the energy supplied to the rotor is concerned, with this embodiment, of our invention there is an additional governing action which makes for even more sensitivity of performance and more accurate speed control than is otherwise obtained. This further action is based upon small amounts of power absorbed by the governor so as to produce more instantaneous action than is produced by the air control mechanism alone. When less power is demanded of the turbine rotor 95', as explained above, the turbine rotor tends to speed up slightly and hence to force the governor weight buttons 500 more tightly against the face of disc 400 causing the rotation of the disc which reduces the air supply. In addition to this action more pressure between the weight buttons 500 and the face of disc 400 causes power to be absorbed by the friction between weight buttons 50!) and disc 40!). This absorption of power by friction immediately disposes of some of the excess power produced by rotor 95' and hence also helps to prevent an increase in speed. Conversely, as under normal operating conditions, there is a slight pressure between the weight buttons 500 and disc 400, it the power load on the turbine rotor 95 is suddenly increased, a slight reduction of speed occurs and the weight buttons soc bear with less pressure against the face of disc "II as explained above, hence, in addition to the action of the governor on the flow of air, less friction is produced between the weight buttons and the disc and hence less power is absorbed by friction which additional power is available to help overcome the additional load imposed upon the turbine rotor 95.

In this embodiment of our invention, therefore, the power absorption principle has been utilized to its best possible advantage in addition to the principle of control of the input energy to the turbine rotor.

As aforementioned the speed control means in accordance with the invention comprise a first element, capable of mechanical movement induced by the operation of the arm or arms, and a second element, cooperating with the first element to effect any desired speed variably adjustable within the entire speed range. Thus, for instance, referring to Fig. 5, brake disc 2116 constitutes the first element operated by the movement of the spring arms 200 by way of the buttons 202 and clip 201. The second element constitutes in this case the friction face 225 of spider iii variably adjustable within the range of mechanical movement of the brake disc 206 as controlled by the deflection of the spring arms 200 between minimum and maximum speeds of the rotor II.

Alternatively as seen in Fig. 14, the first element may be defined by the friction buttons 20! operated by the deflection of the spring arms 200 the second element in this case being the friction face 226' operating and variably adjustable similar to the second element described in connection with Fig. 5. Further modifications of first and second elements in construction and operation similar to those exemplified by Figs. 5 and 14 are illustrated in Figs. 15 and 16.

Specifically referring to Fig. 18, the first element comprises valv plunger 8 operated by the movement of the spring arms 200 by way of the buttons 20!, clip "I, hub 60! and pins 300 and "I. The second element in this case is valve seat III] of valve body 301 variably adjustable within the range of mechanical movement of the valve plunger 3" as controlled by the deflection of the spring arms 2 between minimum and maximum speeds of the rotor 95. Referring to Figs. 19 and 20, the first element comprises friction buttons 500 operated by the deflection of the spring arms 2"; the second element in this case is the disc m. In this instance, the initial position of the first element, 1. e., the friction buttons III is variably adjustable with respect to the position of the second element or disc m by means of the adjustment of the entire rotor assembly within the range of mechanical movement of the friction buttons GM as controlled by the deflection of the spring arms 2" between minimum and maximum speeds of the rotor 95'.

Our invention is not limited to the construction of a spray gun illustrated in the foregoing examples and may be used in connection with any other suitable gun constructions of the wire feed type, including those having other heating or melting means for the wire, such as an are or the like and further including those constructions of this type in which multiple wires are fed to the heating zone.

Although within the preferred embodiments exemplified in the foregoing figures the speed control mechanism is illustrated in connection with a motor of the air turbine type, it is within the scope of our invention to use our novel speed control construction to govern other types of compressed gas motors in wire feed type metal spray guns.

The present application broadly covers a speed governing mechanism having speed control means eifecting speed control of a rotor of a metal spray gun of the wire feed gasblast type by elements cooperating by mechanical movement and actuated by centrifugally operated and angularly defiectable arms; our co-pending application Serial No. 421,195 covers a speed governing mechanism having speed control means with friction elements; and our co-pending application Serial No. 421,196 covers a speed governing mechanism having speed control means regulating the compressed gas supply to the turbine of the metal spray gun.

The foregoing specific description is for purposes of illustration and not of limitation and it is therefore our intention that the invention be limited only by the appended claims or their equivalents wherein we have endeavored to claim broadly all inherent novelty.

We claim:

1. A variable speed governing mechanism for a metal spray gun construction of the wire feed type having a compressed gas motor, comprisin at least one arm, rotatable with the rotor of said motor and centrifugally defiectable for angular deflection with respect to its axis of rotation, against spring resistance, from a predetermined initial position of at least 60 with respect to said axis, speed control means composed of at least one first element and one second element, said first element being positioned and adapted be operatively actedmmfifientrifugal actuation thereof, to cooperate, by mechanical movement, with said second element to thereby efl'ect speed control of said rotor, and a separat mechanism for variably adjusting the relative position between said second element and the initial position of said first element within a range of mechanical movement of said first element defined by angular deflection of said arm between minimum and maximum operating speeds of said rotor.

2. A variable speed governing mechanism for a metal spray gun construction of the wire feed type having a compressed gas motor, comprising a multiple number of substantially co-axially aligned, symmetrically arranged, radial arms, rotatable with the rotor of said motor and centrifugally defiectable for angular deflection with respect to their axis of rotation, against spring resistance, from a predetermined initial position of at least 60 with respect to said axis, speed control means, composed of at least one first and one second element, said first element being positioned and adapted to be operatively acted upon by said arms upon centrifugal actuation thereof, to cooperate, by mechanical movement, with said second element to thereby effect speed control of said rotor, and a separate mechanism for variably adjusting the relative position between said second element and the initial position of said first element within a range of mechanical movement of said first element defined by angular deflection of said arms between minimum and maximum operating speeds of said rotor.

3. A variable speed governing mechanism in accordance with claim 2 in which said arms are at least two spring arms centrifugally deflectable against their spring resistance.

4. A variable speed governing mechanism for a me al spray gun construction of the wire feed type having a compressed gas motor, comprising at least one arm, rotatable with the rotor of said motor and centrifugally deflectable for angular deflection with respect to its axis of rotation, against spring resistance, from a predetermined initial position of at least 60 with respect to said axis, a resilient clip for said arm adapted and positioned to rotate with and bear against said arm, speed control means, composed of at least one first and one second element, said first element being positioned and adapted to be operativelyacted upon by said arm upon centrifugal actuation thereof, to cooperate, by mechanical movement, with said second element to thereby effect speed control of said rotor, and a separate mechanism for variably adjusting the relative position between said second element and the initial position of said first element within a range of mechanical movement of said first element defined by angular deflection of said arm between minimum and maximum operating speeds of said rotor.

5. A variable speed governing mechanism for a metal spray gun construction of the wire feed type, having a compressed gas motor, comprising at least two substantially co-axially aligned,

symmetrically arranged, radial arms, carrying weights adjacent the ends thereof and rotatable with the rotor of said motor and centrifugally deflectable i'or angular deflection with respect to their axis of rotation, against spring resistance, from a predetermined initial position of at least 60 with respect to said axis, at least two resilient clips, one for each of said arms and each adapted and positioned to rotate with and bear against its arm in radially slidable engagement with its arm weight, speed control means, composed of at least one iirond element, said first element being positioned and adapted to be operatively acted upon by said arms upon centgfugal actuation thereof, to cooperate, by mechanial'movemeht with said second element to thereby efieetrspeed control of said rotor,

and a separate mechanism for variably adjustfor a metal spray gun construction of the wire feed type, having a compressed gas motor, the improvement comprising a separate variably adjustable speed setting mechanism for said goveming mechanism and an actuator element for said speed setting mechanism including at least one arm, rotatable with the rotor of said motor and centriiugally defiectable for operative engagement with said speed control means by angular deflection with respect to their axis of rotation, against spring resistance, from a predetermined initial position of at least 60 with respect to said axis.

'1. In a variable speed governing mechanism for a metal spray gun construction of the wire feed type, having a compressed gas motor, the improvement comprising a separate variably adjustable speed setting mechanism for said governing mechanism and an actuator element for said speed setting mechanism including at least two substantially coaxially aligned, symmetrically arranged, radial spring arms, carrying weights adjacent the ends thereof and rotatable with the rotor of said motor and centriiugally deflectable for operative engagement of said weights with said speed control means by angular deflection with respect to their axis of rotation, against their spring resistance from a predetermined initial position of at least 60 with respect to said axis.

HERBERT S. INGHAM. ARTHUR P. SHEPARD.

Certificate of Correction Patent No. 2,381,931.

August 14, 1945.

ARTHUR P. SHEPARD ET AL.

., Itishepeby certified that errors appear in the printed specification of the above numbered $819611; requiring correction as follows: Page 2, second column,

K 1 page 3, second column, line 43, for first column, has 16, for disc 266 read disc 206; page 9, first column,

line 20, for axis or read axis of; page 7, line 29, after jet insert and; and that the said Letters Patent should he read with these corrections therein that the same may conform to the record of the case in the Patent Signed and sealed this 11th day of December, A. D. 1945.

[sun] LESLIE FRAZER,

First Assistant Commissioner of Patents, 

